Water Penetration Depth Research Articles

Properties of high volume glass powder concrete

Mechanical and durability properties of concrete with cement replaced by finely grounded glass powder in high volume up to 60% were investigated. XRD and TGA analyses indicated that the fine glass powder reacted with calcium hydroxide to form calcium-silicate-hydrates. As such, the microstructures of concrete were more compact and homogeneous, especially at the interfacial transition zone. Concrete with cement replaced by 15% and 30% glass powder exhibited the highest strength increase and correspondingly the lowest porosity. Beyond a replacement of 30%, calcium hydroxide became insufficient for the pozzolanic reaction of glass powder. However, the high volume glass powder concrete retained distinct resistance against water and chloride ingress, due to the reduction in pore size and connectively. Reductions of 77%, 83%, 96%, 91% and 92% were observed respectively for water penetration depth, sorptivity, conductivity, chloride diffusion and migration coefficients in concrete with cement replaced by glass powder by 60%.

Visualization and quantification of weathering effects on capillary water uptake of natural building stones by using neutron imaging

Building stones are frequently subjected to very intense degradation due to salt crystallization, often responsible for strong modifications of their pore network. These effects have a great influence on the mechanical properties and durability of the materials, and on the penetration of water. Therefore, the quantification and visualization of water absorption into the pore network of degraded stones could provide useful information to better understand the weathering process. In this study, neutron radiography has been used (1) to monitor and visualize in two dimensions the capillary water uptake in a Sicilian calcarenite widely used as building and replace stone (namely Sabucina stone) and (2) to quantify the water content distribution, as a function of time and weathering degree. Additionally, traditional experiments based on gravimetric methods have been performed, following the standard recommendations. Results demonstrated a change in the physical properties of Sabucina stones with the intensification of the degradation process, with severe effects on the capillary imbibition dynamics. The water penetration depth at the end of the experiment was substantially higher in the fresh than in the weathered stones. The water absorption kinetics was faster in the weathered samples, and the amount of water absorbed increased with the number of weathering cycles. Good agreement between classical and neutron imaging data has also been evidenced. However, neutron radiography has allowed retrieving additional spatial information on the water absorption process, and to better understand how salt weathering affects the petrophysical properties of the studied stone and how it influences then the stone response against water.

Influence of limestone size and content on transport properties of self-consolidating concrete

This study assessed influences of limestone powder’ size and content on compressive strength and transport properties of self-consolidating concrete (SCC). Several SCC mixtures were prepared with uniform water-to-cementitious materials ratio and powder content (cement+fly ash+limestone) of 0.45 and 475kg/m3, respectively. Class F fly ash substituted 20% by weight of cement and 10, 15 and 20% of total cementitious materials was replaced with limestone powder having average particle size of 3 or 8μm. Slump flow of 635±25mm, visual stability index of 0 or 1, and maximum passing ability (difference of slump and J-Ring flow) of 37.5mm were used for all studied mixtures. The devised experimental program included compressive strength, absorption, rapid chloride penetration (RCPT), rapid chloride migration (RCMT), and water penetration depth. The results of this study revealed that inclusion of limestone powder and reduction in its size were both effective in improving compressive strength and transport properties of SCC. While absorption, volume of permeable voids, water penetration depth, and RCPT improved significantly through use of limestone powder, the improvements were marginal for compressive strength and RCMT. Reduction of limestone powder size had more effect in improving performance of 28-day cured concrete as compared to that of 90days mixtures.

Effects of hydrostatic pressure on chloride ion penetration into concrete

Chloride ion penetration is the main cause of steel corrosion in reinforced concrete, and significantly aggravates the degradation of concrete durability. With the development of concrete structures that are hydraulic or situated in the ocean, concrete is more often subjected to environments with high hydrostatic pressure. This paper investigates chloride ion penetration into concrete under a hydrostatic pressure environment. Fresh concrete and concretes mixed with various mineral admixtures are prepared, and the influence of the value and application time of hydrostatic pressure on chloride ion penetration is explored. Results show that hydrostatic pressure significantly increases chloride ion penetration, especially when a high hydrostatic pressure is applied. Concrete mixed with mineral admixtures possesses a better resistance to chloride ion penetration compared with fresh concrete; in particular, the improvement is more obvious when concrete is mixed with both mineral powder and fly ash. Reducing the water-to-cement ratio is an effective method to improve the resulting concrete's resistance to chloride ion penetration. Under an environment producing hydrostatic pressure, water and chloride ion penetration are not synchronous, and the water penetration depth is much higher than the chloride ion penetration depth.

Hybrid Dendrimers of PPI(core)-PAMAM(shell): A Molecular Dynamics Simulation Study.

The structural properties of hybrid dendrimers PPI(core)-PAMAM(shell) for application in drug delivery are studied by coarse-grained molecular dynamics simulation, and their capacity to encapsulate drug guest molecules such as pyrene is investigated by changing the core (PPI) in the PPI-PAMAM hybrids. For this purpose, a coarse-grained model for PPI dendrimer is developed and is used to predict the structural properties as a function of PPI core size, such as the size of hybrid dendrimers, the depth of water penetration, the extent of back-folding of their chain terminals, the size and distribution of created cavities, and asphericity. The results show that the location of pyrene in the interior structure of the hybrids is independent of PPI core size and the branching chains create a barrier against the penetrating molecules in the shell of PPI. Then, by adding the PAMAM to the surface of PPI, this barrier is removed, and this will enhance the encapsulation capacity of the hybrid.

Experimental Analysis of the Impact on the Durability of Concrete Additions

This report deals with long term monitoring of durability properties of concrete using different weight doses of various kinds of additions. Particularly limestone, silica fume as a 50% suspension and blast furnace slag were used. Even though the basic recipe is based on the designed concrete, all the fresh concrete was made with a free-fall concrete mixer in the laboratory. This report deals with long-term monitoring of cement concrete surface resistance to water and defrosting chemicals (achieved 475 cycles). The article also describes results of following tests: determination of concrete frost resistance, depth of water penetration under pressure and depth of chloride penetration. Standard tests of fresh and hardened concrete specimens complement the experiment.

Evaluation of the Influence of Specific Surface Treatments of RBA on a Set of Properties of Concrete.

High water absorption of recycled brick aggregate (RBA) is one of the most discussed parameters in terms of its application in the production of concrete—its influence on the amount of mixing water and, hence, the quality of the concrete, is usually considered negative. In this paper, different methods of decreasing the absorption of RBA and, consequently, the impact on the properties of concrete, are described. The RBA has been treated to decrease the water absorption capacity by impregnation approach using specific impregnators. Afterwards, the RBA samples have been dried at two different temperatures in the laboratory oven—20 and 90 °C. Concretes using 4/8 fraction of the treated RBA instead of natural aggregate (NA) have been mixed and tested. The effectiveness of the RBA treatments have been evaluated on the basis of their influence on the properties of the hardened concrete; by means of the following tests: flexural strength, compressive strength, capillarity, total water absorption capacity, depth of water penetration under pressure, and frost resistance. The method of ranking by ordinal scale has been used as it is suitable for the comparison of a large set of results, while results have been analyzed in terms of the most important technological parameter that influences the quality of the concrete-effective water content. Out of all the tested surface-treatments of RBA, treatment by sodium water glass has the best potential for reduction of the water/cement (w/c) ratio. When the effective w/c ratio is kept within standard limits, concretes containing treated RBA are possible to be specified for various exposure classes and manufacturing in practice. The experiment confirms that at a constant amount of mixing water, with decreasing water absorption of RBA, the effective amount of water in the concrete increases and, hence, the final properties of the concrete decrease (get worse). As the water absorption of the RBA declines, there is a potential for the reduction of the w/c ratio and improvement in the quality of the concrete.

Improvement in concrete resistance against water and chloride ingress by adding graphene nanoplatelet

Graphene nanoplatelet (GNP) is a cheap impermeable carbon-based nanoplatelet with large surface-to-volume ratio and has been exploited in polymer materials to improve their transport resistance. Experimental investigation on the transport properties under chloride and water exposure was carried out on concrete containing up to 2.5% of GNP at 0.5% increment. The pore structure was inferred using mercury intrusion porosimetry and significant reduction in pore sizes was measured. Concrete with 1.5% of GNP showed the greatest reduction in transport; water penetration depth, chloride diffusion, and migration coefficients were reduced by 80%, 80%, and 37%, respectively. The barrier effects of GNP were characterized and it was found that more than 50% of the improvement in transport resistance can be attributed to tortuosity while the rest to pore refinement. However, further improvement did not take place at GNP content higher than 1.5% due to limitation in dispersing the nanoplatelet clusters.

Absorption Characteristics of Cement Combination Concrete Containing Portland Cement, fly ash, and Metakaolin

The resistance to water penetration of cement combination concretes containing Portland cement (PC), fly ash (FA), and metakaolin (MK) have been investigated at different water/cement (w/c) ratios, 28-day strengths, and depths of water penetration using their material costs and embodied carbon-dioxide (eCO2) contents. Results revealed that, at equal w/c ratio, eCO2 content reduced with increasing content of FA and MK. MK contributed to the 28-day strengths more than FA. Compared with PC, FA reduced cost and increased the depth of water penetration, MK increased cost and reduced the depth of water penetration, and their ternary combinations become beneficial. At equal strengths and levels of resistance to water penetration, most of the cement combination concretes are more environmentally compatible and costlier than PC concrete. Only MK binary cement concretes with 10%MK content or more and ternary cement concretes at a total replacement level of 55% with 10%MK content or more have higher resistance to water penetration than PC concrete.

Improvement on microstructure of concrete by polycarboxylate superplasticizer (PCE) and its influence on durability of concrete

In this study, the influence of polycarboxylate superplasticizers (PCEs) on durability of concrete was investigated. Carbonation, water impermeability and rapid chloride permeability of concrete with different types of polycarboxylate superplasticizer and polynaphthalene superplasticizer (PNS) were tested. In order to obtain deeper insights into the influence of PCE on concrete durability, microstructure in the concrete was explored by means of mercury intrusion porosimetry (MIP), thermogravimetry (TG) and nano-indentation technique. Smaller carbonation depth, water penetration depth and better resistance to chloride ion penetration show that concretes with PCE have better durability performances than concretes with PNS. MIP results show that the mortars with PCE have lower porosity than that with PNS. The fraction of pores with diameters larger than 100nm in the mortars with PCE is lower than in the mortar with PNS. According to TG tests, there are more hydration products in the cement pastes with PCE than in the cement pastes with PNS. Nano-indentation tests show a higher ratio of high density C–S–H to low density C–S–H in the cement paste with PCE than in the cement paste with PNS. It can be concluded that PCE leads to denser microstructure in concrete than PNS and, therefore, better durability performances of concrete.

STUDY OF CORAL BLEACHING MAPPING USING HIGH RESOLUTION IMAGES (A case study: The Water Area of PLTU Paiton Probolinggo)

The rising temperature of Andaman Sea in May 2010 causing many Indonesia’s waters experienced 4°C temperature rise. This phenomena triggers coral bleaching in many Indonesia’s coastal area, one of them is Probolinggo beach. Probolinggo beach is a beach with very fascinating coral reefs, one of them is located near Paiton Power Plant area. Paiton plant unit is a power plant that is owned by PT. PJB which used to supply almost three of fourth part of the electricity in Java and Bali. PLTU Paiton is established at the seaside of Probolinggo beach, which has a coolant circulation system located adjacent to the sea. Coral bleaching mapping with remote sensing method with in situ data was used to detect the extent of areas experiencing coral bleaching. WorldView-2 Satellite Imagery was used with the processing performed on the blue bands and green bands which has the depth of water penetration. Water column correction is done to eliminate the effect of depth. Supervision classification is performed to get the alleged spot of coral bleaching. Classification results showed that the total area of the bleached corals from the five-point field observations with area of each point is 100m^2 is ± 726 m^2.The coral bleaching phenomenon in Paiton’s Power Plant coastal waters is caused by two main factors, the former is the rise of sea surface temperatures and the latter is the activity of Paiton itself. Dredging activities for the construction of new generating units and water discharge processing activities plant added the negative effect for the bleaching, aside from rising sea surface temperatures of ± 4° C.

Properties of high strength concrete containing scrap tire rubber

Disposal of waste tire rubber has become a major environmental issue in all parts of the world representing a very serious threat to the ecology. One of the possible solutions for the use of scrap tire rubber is to incorporate it into concrete, to replace some of the natural aggregate. This paper presents the results of an experimental research to analyse the suitability of scrap tire rubber as a partial substitute for natural fine aggregate in high strength cement concrete. Crumb rubber replaced natural fine aggregate from 0% to 20% in multiples of 2.5%. Tests were performed to determine the compressive strength, flexural tensile strength, pull-off strength, abrasion resistance, water absorption and water penetration of these concrete samples and their microstructures were observed using Scanning Electron Microscopy (SEM). It was observed that the compressive strength, flexural tensile strength, pull-off strength and depth of water penetration of the rubberized concrete were less than that of the control mix, while the abrasion resistance and water absorption (up to 10% substitution) exhibited better results than that of the control mix concrete. Rubberized concrete may be used in structures where there are chances of brittle failure. Crumb rubber may be utilized in high strength concrete as a partial substitute for fine aggregate up to 12.5% by weight for obtaining strength above 60 MPa.

Effects of vegetation at different succession stages on soil properties and water flow in sandy soil

AbstractThe effects of vegetation at different succession stages on soil properties and water flow were assessed in sandy soil at 3 experimental sites near Sekule village (southwest Slovakia). Site S1 was a pioneer site dominated by mosses, site S2 was an early successional stage with a thin stand of grasses, and site S3 was an early successional stage (more advanced compared to the previous), richer in species, with a denser stand of grasses. It was found that vegetation at different succession stages affected soil properties and water flow in sandy soil, but the order of changes in some soil properties and water penetration depths were different from the order of succession stages.

Conformational Equilibria of Organic Adsorbates on Nanostructures in Aqueous Solution: MD Simulations

Atomistic molecular dynamics (MD) simulations of bulk aqueous solution of NaCl and functionalized gold nanoparticles (GNPs) in aqueous solution were conducted at 300 K. Bulk NaCl solution systems of different concentration have been studied using various force field parameter sets to investigate aggregation of ions and to choose suitable force field parameters for ions. Gold nanoparticles functionalized with linear and branched hydrocarbon chains with different grafting density (d f =1, 2/3 and 1/3), chain length ((CH 2 ) l , l=5, 11, 17 and 23), position of the branching point (4th, 8th and 12th carbon) and terminal groups (CH 3 , COO − and NH +3 ) were modeled to investigate various phenomena at the microscopic level. The solution of a functionalized GNP with ionic terminations was neutralized by excess Na + and Cl − ions. Focus has been given to the penetration depth of water and ions into the diffuse shell of alkanethiols as a function of grafting density, functionalization and chain length. Special focus has been given to the relative accessibility of the gold core by water in dependence of grafting density, chain length and chain shape. The orientation of water molecules inside the hydrocarbon chain environment (from the surface of the gold core to the terminal groups) and near the terminal groups has been studied in detail. Hydrogen bonds between water and polar terminal groups have also been studied. Special attention has been given to the solvent accessible surface area (SASA) of functionalized GNPs, and the coating asymmetry and ways to prevent it. It is observed that the penetration of water and ions into the hydration shell of alkanethiols increases with decreasing grafting density, irrespective of the terminal group of the hydrocarbon chains. High grafting densities lead to more extended hydrocarbon chains which behave more rigidly. The solvent accessible surface area (SASA) is dependent on the chain length and the terminal group. SASA (per unit chain length) of COO − group terminated GNPs with chain length (C l ) 5 is the highest among all GNP coated with linear chains. Water molecules orient near the surface of the gold core pointing one hydrogen towards the center of the gold core irrespective of chain length, terminal group and grafting density. Water molecules cannot access the surface of the gold core of a branched chain GNP as easily as in the linear chain GNP. Branched chains protect the core better than the corresponding linear chains. Among all studied systems, nonpolar group terminated branched chains with chain length 17 and branched at the 4th carbon atom provide the best protection to the nanoparticle core. Coating asymmetry is generally more prominent for longer chains (>11), and the asymmetry can be prevented by introducing branching points.

Effect of aggregate gradation with fuller distribution on properties of sulphoaluminate cement concrete

Experimental investigations on mechanical property and durability of sulphoaluminate cement concrete with aggregate gradations according to Fuller distribution are presented in this paper. Compressive strength, water impermeability and resistance capability to sulfate attack of SACC have the same trend of concrete with fine aggregates of Fuller distribution gradation<concrete with coarse aggregates of Fuller distribution gradation<concrete with total aggregates of Fuller distribution gradation. The relationship between bulk density of aggregate and water penetration depth obeyed the second-order polynomial y=0.002x2-6.863 8x +5 862.3, and had a notable correlation R2=0.979 9. The sulphoaluminate cement concrete with total aggregate gradation with Fuller distribution for h=0.50 had the best resistance capability to sulfate attack. It was a second-order polynomial relationship between bulk density of aggregates and water penetration depth of y=0.002x2-6.863 8x+5 862.3 with R2=0.979 9, which indicated notable correlation. The fitting formula between bulk density of aggregates and sulfate resistance coefficient of SACC was y=0.000 5x+0.370 4 with R2=0.958 5.

Is colour change a good measure of a water penetration front?

GARField nuclear magnetic resonance (NMR) profiling is used to demonstrate that the sharp colour change boundary commonly used to locate the water front in cement and concrete capillary absorption tests is a poor indicator of the true depth of water penetration. Across a range of mortars and concretes, NMR invariably shows a smooth and often near-zero gradient in the degree of saturation at this boundary. Any sharp front that does exist, as might arise from a strong dependence of the effective diffusivity on concentration and a multi-modal pore size distribution on the nanoscale, is always far beyond the colour change line.

Study on waterproof mechanism of polymer-modified cement mortar

In order to clarify the effect and influence mechanism of polymers on the waterproof performance of cement mortar, the effects of three polymers on capillary water absorption, impermeability, porosity and cracking of cement mortar were studied. The correlation between porosity and waterproof performance was analysed and the waterproofing mechanism of polymer-modified mortar was explored. The results show that waterproof performance, characterised by capillary water absorption and impermeability, was significantly improved by all three polymers but to different extents. The cracking weighted value declined and open porosity decreased with an increase in polymer dosage. The penetration depth of water into mortar and the capillary water absorption showed linear and exponential growth, respectively, with an increase in open porosity. The polymers were found to improve pore structure and refine porosity of &gt;50 nm and thus weaken the negative effect of porosity on the waterproof performance of mortar.

Macropore–Matrix Water Flow Interaction around a Vertical Macropore Embedded in Fine Sand—Laboratory Investigations

Infiltration experiments were conducted in a large‐scale container setup to investigate water flow through a macropore and between the macropore and the surrounding porous media matrix. The experimental container had a height of 120 cm. Its base was a half disk with a diameter of 100 cm. The container was built from stainless steel with an observation glass window as a section plane. It was homogeneously filled with fine sand. An artificial macropore was placed vertically along the centerline of the glass pane. Tensiometers embedded throughout allowed for a continuous observation of pore water pressure heads. During the injection of water into the macropore, interval photography was employed to visualize the propagation of the water front in the matrix. It was shown that water is being imbibed into the surrounding matrix due to capillary forces, thus depleting the discharge in the macropore. For initially dry sand, this matrix–macropore interaction effectively limits the penetration depth of water inside the macropore. Only after long injection periods (&gt;8 h for low injection rates) with a concurrent increase in water saturation in the porous matrix around the macropore does the vertical macropore flow increase successively and thus a penetration to deeper zones is detected. For all injection rates the water distribution in the matrix was observed visually and showed that for small and medium flow rates the lateral distribution in the matrix temporarily predominated the vertical inflow in the macropore. The experimental design allowed for the calculation of transfer velocity in water flows between the macropore and the surrounding matrix. Furthermore the transfer velocities could be related to the water pressure head in the surrounding fine‐grained sand matrix. Here a distinct decrease of transfer velocity from dry to wet conditions was observed. The transfer velocities obtained were discussed and compared with the results from similar experiments conducted by other authors. These experiments provide a large data set and thus a sound basis for testing and improving numerical models.

Using microwave near-field reflection measurements as a non-destructive test to determine water penetration depth of concrete

A non-destructive version of a standard test for concrete permeability has been demonstrated. The method is based on water penetration depth estimation from near-field microwave measurements using an open-ended rectangular waveguide. In particular, water penetration is determined from the differential measurement of reflection coefficient in the S-band before and after injection of water under pressure. Experimental results show a good correlation between the standard destructive test and the new method. Microwave measurements simplify the standard test avoiding the need of drilling out a sample from the structure and thus reducing both the cost and time needed in the analysis.

Transport Properties of Concrete with Glass Powder as Supplementary Cementitious Material

The study reports a sustainable solution to enhance concrete durability performance by using recycled glass powder as a supplementary cementitious material. Portland cement was replaced at different contents: 15, 30, 45, and 60% by weight. All concrete mixtures containing glass powder showed lower permeability compared to plain concrete. Particularly, 30% was identified as the optimum replacement for glass powder because the highest compressive strength was achieved. For this replacement, chloride diffusion and migration coefficient, water penetration depth, and sorptivity were found to be reduced by 87, 36, 65, and 61%, respectively. The improvements in those transport properties are attributed to the pozzolanic reaction of glass powder, which turned calcium hydroxide into calcium-silicate-hydrates. The microstructure of the formed cement paste and interfacial transition zone is refined and less porous, and therefore more resistant to ingress of harmful fluids and agents.